GP32 Intensity Bit

[DaveC]

Ermm. Isn't this thread over-simplifying the problem somewhat? As I understand it, the intensity bit simply makes the colour slightly lighter.

So if you set it to 0 for everything all your colours are going to be darker. Sure your blacks are going to be real 'black' not grey, but your whites aren't going to be full 'white' then. Which IMHO is worse, but then again I'm biased because I have no backlight.


Don't we need a nice formula relating R G B and I?

e.g. if I have r=30 g=30 b=30 i=0, is that the same as r=0 g=0 b=0 i=1?

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Yes that formula makes sense. But the first one is more flexible. With that you have the option to set RGB to 0,0,0 AND you can set white to RGB 255,255, 255 giving the best contrast. but with the second the lowest you can ever get will be RGB 30,30,30, but still the highest white you can get is still 255,255,255 (you won't get 285,285,285 with the intensity bit) so you get less contrast which is *worse*.

Believe me I have seen the difference on my BLU and the difference is great (NLU,FLU doesn't make much difference though) The whites are the same with the I bit but the blacks are grey and it looks awful and washed out, kind of like you have a crappy LCD that has a poor black level, like an old Lynx or Game Gear.

 

[pea]

The whites are the same with the I bit but the blacks are grey and it looks awful and washed out

Personally, I had issues with the whites being different. I was loading a mostly white image and displaying it fullscreen and my image loading routine sets the intensity bit to 0, so so-far so-good.

I then drew a solid rectangle over the image with color 0xffff which I assumed was white, but is actually white with the intensity bit set to 1 (the real value should be 0xfffe).

I can't recall which way it went, but either the image or the rect was noticably lighter, even though both were presumably white.

It drove me nuts for a while - I had all sorts of theories - my image loading routine is screwing the palette? Maybe the way the LCD works, the most recent colours are brighter? I tell you - many hours of debugging for nothing.

 

[DaveC]

Not sure but look at DrMD or fGEN for example. It does not have the Intensity set now and the whites are just as bright as when it was set (the first version). Not sure what the code for it is but I just know it looks much better with it off.

Again the comparison Drmd first version with the bit on, fGen with the bit off:

Notice with these the whites look about the same? Actually they look brighter in the image with the bit off, but that is an illusion, the better contrast without the intensity bit makes the whites appear brighter, even though they are the same. An LCD can only go so light after that limit it doesn't matter what is done in code.

 

[pea]

dude, no offense, but using that as your evidence is balls!
The only way to tell is to draw two white bars, one with I bit set, and one without